Abstract

The 2p 6d feature in the $Bi L_3$ spectra has different energies in the semiconducting $(0.0\leq x<0.7)$ and the superconducting (x=0.75) compositions of $BaBi_{1-x}Pb_xO_3$. The Bi 4f core level spectrum shows distinct features ascribable to Bi III and Bi V in $BaBiO_3$ and in the semiconducting compositions; the width of the 4f peaks is also considerably larger in these compositions compared to that in $BaBi_{0.25}Pb_{0.75}O_3$, which shows a single sharp Bi 4f feature.